N-乙酰半胱氨酸减轻香烟烟雾提取物所致的A549细胞损伤

NAC relieves the A549 cells injury induced by cigarette smoke extract

目的研究N-乙酰半胱氨酸(NAC)对香烟烟雾提取物(CSE)暴露后的A549细胞的影响。方法 MTT法测定不同处理后A549细胞的存活率;用PI单染和AnnexinV-FITC/PI双染检测细胞的周期变化和凋亡变化;用荧光探针H2DCFDA检测细胞内活性氧簇(ROS)变化;用实时荧光定量PCR和Western blot技术检测胰岛素样生长因子结合蛋白-3(IGFBP-3)的表达变化。结果 CSE致A549细胞存活的A值为0.55±0.04,显著低于对照组的0.78±0.03(P<0.05),NAC处理使A值显著上升至0.67±0.04(P<0.05),并消除了G1期阻滞,降低细胞凋亡率等。IGFBP-3的表达在CSE刺激后,有所升高,在接受NAC保护后,其表达水平有所降低(P<0.05)。结论 NAC可以抑制香烟烟雾提取物造成的A549细胞损伤,IGFBP-3可能在香烟烟雾提取导致细胞损伤的机制中发挥作用。

Objective To study the protective role of N-acetylsteine in the A549 cell injury caused by cigarette smoke exact and the expression change of insulin-like growth factor binding protein-3 in this process. Methods MTT assay was used to evaluate cell viability. Cell cycle and apoptotic cell proportion in each group detected re-spectively by PI and AnnexinV-FITC / PI double-labelled flow cytometry. Intracellular reactive oxygen species（ROS）was estimated by fluorescent indicator H2DCFDA. DAPI was used to observe the nuclear morphology. Fur-thermore,using real-time quantitative RT-PCR as well as western blot methods,the expression level of IGFBP-3 was detected. Results Compared with control group（0. 78 ± 0. 03）,CSE inhibit cell proliferation significantly（0. 55 ± 0. 04）. NAC can reduce cell injury caused by CSE including restoring the viability of A549 cells（0. 67 ± 0. 04）, attenuating G 1 block of cell cycle and significantly reducing the proportion of apoptotic cells and so on. High ex-pression of insulin-like growth factor binding protein-3（IGFBP-3）in A549 cells treated with CSE was found at both transcriptional and protein levels,and concomitant with the restoration of cell growth after treatment with NAC,down regulation of IGFBP-3 was observed. Conclusions It is concluded that NAC can antagonize CSE-in-duced growth arrest of alveolar epithelial cells and that down regulated IGFBP-3,which probably play an important role in this process.